Mechanical movement.



PATENTED SEPT. 5, 1905.

' K. KNUDSEN. MECHANICAL MOVEMENT.

APPLIUATIOH FILED JULY 11, 1904.

No. 798,907. PATBNTED SEPT. 5, 1905. K. KNUDSEN.

MECHANICAL MOVEMENT.

APPLIOATION nun JULY 11, 1904.

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No. 798,907. PATBNTED SEPT. 5, 1905.

K. KNUDSEN.

MECHANICAL MOVEMENT.

APPLICATION rum) mm 11, 1904.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

KARSTEN KNUDSEN, OF CHICAGO, ILLINOIS, ASSIUNOR 'IO HOLSON MOTOR PATENTS COMPANY, LTD., OF GRAND RAPIDS, MICHIGAN, A LIMITED PARTNERSHIP OF MICHIGAN.

MECHANICAL MOVEMENT.

Specification of Letters Patent.

Patented Sept. 5, 1905.

To all whom it may concern.-

Be it known that I, KARs'rnN KNUnsnN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Mechanical hflovements, of which .the following is a specification.

This invention relates to improvements in mechanical movements, and refers more specitically to an improved power-transmission gearing.

Among the salient objects of the present invention are to provide an apparatus embodying novel features of construction in the gear members and the arrangement of the cooperating parts whereby the separating thrust incident to the use of inclined gear-teeth is utilized to effect an automatic adjustment of the driving engagement of the parts to compensate for inaccuracies in the mechanical construction and adjustment, to provide a construction in which bevel-gears having spirallyformed teeth may be employed and the lateral thrust incident to the engagement of the inclined teeth neutralized by opposing the thrust of one gear to that of another similar reversely-disposed gear, to provide an im proved construction whereby the advantages of a certain type of power-tranmission mechanism heretofore known are availed of, while at the same time the advantages incident to the use of bevel-gears having spirally-formed teeth are also secured, and in general to provide a simple and improved mechanism of the character referred to.

To the above ends the invention consists in the matters hereinafter described, and more particularly pointed out in the appended claims.

The invention will be readily understood from the following description, reference being had to the accompanying drawings, in which Figure I is an axial sectional view of a wheelhub equipped with one embodiment of my invention, certain parts within the wheel being shown in elevation and others in section. Fig. 2 is a face view of the mechanism within the wheel looking toward the left-hand side, as viewed in Fig. 1, the greater part of the easing of the wheel being broken away to expose the internal parts. Fig. 3 is a detail of the main drive-shaft and gears connected therewith, a motor-armature mounted upon the shaft being shown partly in section and partly in elevation. Figs. 4, 5, and 6 are details of the gears, showing particularly the construction of the spiral teeth thereof.

The mechanical movement forming the subject of the present invention is shown in the present instance as embodied in a hub-motor of the general type set forth and described in patent to Holson, No. 701,341, dated June 3, 1902. .It is to be understood, however, that the invention is in no sense limited to this particular embodiment, but, on the contrary, is capable of general application, whether the object be to reduce or increase the speed and whether the structure be a self-contained one, as in the ease of a hub-motor, or simply an adjunct for transmitting power from one point to another.

IVith the above explanation in mind a description of the particular embodiment of the invention shown herein is as follows: Describing first the general arrangement of parts and referring to Figs. 1 and 2, 1 designates an end portion of a vehicle-axle, and 2 designates as a whole a hollow wheel journalcd thereon. Said wheel comprises a hub portion 3, litting upon thejournal of the axle, a rim 4, provided with a suitable tire 5, and two internally-concave and outwardly-convex side plates 6 and 7. \Vithin the hollow wheel thus formed is arranged a motor mechanism, (designated as a whole 8.) Two. Iield members 9 and 10, respectively, are lixedly supported upon the wheel-axle 1 and together constitute a rigid hollow shell within which is journaled the armature or rotating member of the motor and its shaft.

Describing the motor mechanism more specifically, l1 designates as a whole a driveshaft constituting the armature-shaft of the motor and provided at each end with a driving-pinion, as 12 13, respectively, and rigidly mounted thereon. Upon the inner faces of the side plates 6 and '7 of the wheel, concentrically with the axis of the latter and in opposed relation to each other, are mounted two annular racks H and 15, with which the pinions 12 and 13, respectively, engage.

I6 16 designate bearing-sleeves mounted upon the opposite ends of the armature-shaft and within which the latter is journaled. It will be noted by reference to detail Fig. 3 that the construction of these sleeves 16 and the journal portions 17 of the armature-shaft is such that a limited bodily endwise movement of the shaft is permitted, each journal-box be ing to this end provided with an annular recess 18, within which operates an annular rib 19 upon the shaft. The journal-boxes 16 are clamped between and rigidly supported by pairs of arms 20, forming extensions of the castings of the field members, which latter are rigidly mounted upon the axle, as inclicated at 21 in Fig. 1. I

The details of construction of the motor form no part of the present invention, and it will be suflicient, therefore, to say that the armature of the motor is mounted upon and has rigid driving engagement with the driveshaft 11, while the field members are mounted so as to substantially inclose and stand in proper operative relation to the armature.

From the foregoing description, together with reference to the drawings, it will be understood that the drive-shaft extends diametrically across and diagonally between the two pairs of duplex racks 1 1 and 15, the pinions 12 and 13 being engaged with the respective racks l4. and 15 at diametrically opposite points.

Describing now more specifically the construction of the rackand-pinion teeth, and referring more particularly to Figs. 4, 5, and 6, showing these parts in detail, the raclimembers l4 and 15 are provided with inwardlyfacing teeth 22, which are formed to extend radially and spirally, each rack member being slightly beveled or having its teeth disposed at a slight angle to a plane perpendicular to the axis of the gear. The teeth 22 are correctly generated on a logarithmic spiral, the particular curvature of this spiral not being essential, but being capable of variation. The angle of inclination or degree of curvature of the spiral is, however, intentionally chosen such as to induce a more or less pronounced endwise thrust upon the drive-shaft for a purpose which willhereinafterbe explained. The

Y pinions 12 and 13 are of course suitably beveled to properly intermesh with their respective racks, with the drive-shaft arranged in the diagonal position described, and the teeth 23 are generated in conformity with the usual method, so as to properly intermes'h with the teeth 22, it being understood that the degree of spirality of the teeth 22 will determine the form of the teeth 23, as will be well understood by those skilled in the art. With the teeth thus generated there is, as to each pinion, a traveling point of contact between each successive tooth and the corresponding tooth of the rack, the inclined relation of the teeth to each other insuring that there will be no interruption of engagement between successive teeth, and therefore that the gearing will be practically noiseless.

Inasmuch as the drive-shaft extends diagonally between the two racks and the pinions thereof engage their respective racks in diametrically opposite relation, it follows that the separating thrust between each rack and its pinion is opposed and neutralized by the corresponding thrust of theopposite rack and pinion so long as the shaft is held against movement laterally by its bearings. It will be evident upon consideration of the manner of engagement between the two pinions and their respective racks that the endwise thrust imparted to the drive-shaft by the spirality of the teeth of one pinion will be exactly counteracted by the counter-thrust on the shaft of the opposed pinion. However, it will be further evident that if there exist inequalities in the construction or spacing of the gearteeth of either or both racks such inequality may be and will be automatically compensated for by an endwise shifting of the shaft bodily, and with itthe pinions, in the proper directions notwithstanding both rack members are rigid with each other and both pinions are rigid with the driveshaftthat is to say, if, for example, one of the teeth of one rack is spaced too far in rear of a given preceding tooth then an endwise movement of the pinion relatively to this rack will of course bring the pinion-tooth and rack-tooth into proper bearing because of the oblique disposition of the rack-teeth relatively to the longitudinal axis of the shaft. Since the shaft is purposely made free to move a limited distance in either direction, it follows that all inequalities in the spacing of the teeth of the gearing will be in this manner compensated for and the drive-shaft will impart its driving moment equally or substantially equally through botlrpinions' at all times. This is obviously a feature of great importance in a construction in which the racks are rigid with each other, since mechanical perfection is in practice impossible. It is true that such endwise displacement of the pinions results in a slight displacement of the shaft from its theoretically-correct position; but this is in practice immaterial, since it is necessary to always provide a certain amount of working clearance between the operating parts, which permits such displacement without objectionable effect.

I claim as my invention 1. A mechanical movement, comprising cluplex annular rack members, a drive-shaft, two pinions thereon operatively engaging said rack members at diametrically-opposite points and means for imparting rotation to said driveshaft, said rack members and pinions having spiral-form teeth.

2. A mechanical movement, comprising duplex annular rack members arranged in parallel relation to each other and having their teeth extending radially and spirally with relation to the axis of the racks, and a driveshaft arranged to extend diametrically across,

and diagonally between said rack members, two pinions upon said shaft operatively engaged with the respective racks, said pinions having teeth of suitable spirality to correspond to, and mesh with the teeth of said rack members.

3. A mechanical movement, comprising duplex annular rack members arranged in parallel relation to each other and having their teeth extending radially and formed on logarithmic spiral curves, and a drive-shaft arranged to extend diametrically across and diagonally between said rack members, two pinions mounted upon said shaft and operatively engaged with the respective racks, said pinions having teeth of suitable spirality to correspond to, and mesh with the teeth of said rack members.

In combination, two annular rack members and a shaft, two pinions upon said shaft operativel y engaging the respective members, said rack members and pinions having spiralform teeth and the spirality of the pinions being reversely disposed relatively to each other, whereby the end thrust upon the shaft incident to the driving engagement of one pinion is neutralized by the end thrust upon the shaft incident to the driving engagement of the other pinion. I

A mechanicalmovement, comprising duplex annular rack members rigidly unitedand arranged in parallel relation to each other and having their teeth extending radially and spirally with relation to the axis of the racks, a d rive-shaft arranged to extend diametrically across, and diagonally between said rack members, two pinions rigidly mounted thereon and operatively engaged with the respective racks and bearing-supports for said drive-shaft, said bearings affording endwise bodily movement of the drive-shaft, for the purpose set forth.

6. A mechanical movement, comprising duplex annular rack members rigidly united and arranged in parallel relation to each other and having their teeth extending radially and spirally with relation to the axis of the racks and inclined with relation to a plane perpendicular to said axis, and a drive-shaft arranged to extend diametrically across, and diagonally between said rack members, two bevel-pinions mounted upon said shaft operatively engaged with the respective racks and having teeth of suitable spirality to correspond to, and mesh with the teeth of said rack members.

7. A mechanical movement, comprising duplex annular rack members rigidly united and arranged in parallel relation to each other and having their teeth extending radially and spirally with relation to the axis of the racks and inclined with relation to a plane perpendicular to said axis, a drive-shaft arranged to extend diametrically across, and diagonally between said rack members, two bevel-pinions upon said shaft operatively engaged with the respective racks and having teeth of suitable spirality to correspond to, and mesh with the teeth of said rack members, and fixed bearing-supports in which said drive-shaft is journaled, said bearings affording a limited bodily endwise movement of the drive-shaft.

KARSTEN KNUDSICL'. \Vitnesses:

ALBERT H. (iimvics, FREDERICK (J. (ioopwm. 

